The present invention relates generally to semiconductor devices and methods for manufacturing the same, and more particularly, to semiconductor devices that can prevent or at least minimize the occurrence of cracks and alike from occurring between a support pattern and storage nodes and methods for manufacturing the same.
The demand for high performance semiconductor memory devices continues to rapidly increase. Accordingly, various techniques for obtaining small capacitors that have high capacitance are in demand. The fundamentals of exactly what is required to make a capacitor are relatively simple. A capacitor is an electronic structure that has a dielectric interposed between storage nodes and plate nodes. The capacitance of the capacitor is understood to be proportional to the surface area of an electrode and the dielectric constant of the dielectric and is inversely proportional to the distance between electrodes, that is, the thickness of the dielectric.
In order to obtain a capacitor having high capacitance, it is necessary to use a dielectric having high dielectric constant, increase the surface area of an electrode, or decrease the distance between electrodes. In this regard, physical limitations or barriers exist when trying to decrease the distance between electrodes. That is, the thickness of the dielectric can only be so thin until non-insulative breakthrough will occur. Therefore, advancements in forming small capacitors having high capacitance is mainly directed toward either using dielectric materials that have relatively high dielectric constants or increasing the surface area of the opposing electrodes.
One promising option to achieve a micro sized capacitor having a high capacity is to increase the surface area of an electrode along a three-dimensional configuration instead of being restricted to a two-dimensional scheme. Some popular three-dimensional schemes include concave and cylindrical geometric shapes. Cylindrical capacitors exhibit much larger electrode surface areas as compared to the concave type capacitors. Therefore, cylinder type capacitors promise to provide a number of advantages when applied to highly integrated semiconductor devices.
However, a number of difficulties in fabricating micro sized cylindrical capacitors can occur. In particular, forming the cylindrical type capacitors using a dip-out process to remove the mold insulation layer that serves as a mold for forming storage nodes can result in compromising the integrity (i.e., cracks and alike) of the resultant micro-sized cylindrical capacitors. As the size of cells decreases, the aspect ratio of the storage nodes increases, and the adjacent space between storage nodes becomes narrower. As a result of conducting the dip-out process, these micro-sized cylindrical capacitors are prone to leaning. Under these circumstances, a method of forming support patterns for fixing or buttressing the storage nodes has been proposed in the art.
Hereinbelow, a conventional method for manufacturing a semiconductor device having cylinder type capacitors will be briefly described.
After forming an interlayer dielectric over a semiconductor substrate, storage node contact plugs are formed in the interlayer dielectric. After forming a mold insulation layer for forming storage nodes on the interlayer dielectric including the storage node contact plugs, a nitride layer for supporting storage nodes is formed on the mold insulation layer. By selectively etching the nitride layer for supporting storage nodes and the mold insulation layer, holes for storage nodes are defined to expose the storage node contact plugs.
After forming storage nodes on the surfaces of the holes for storage nodes, by selectively patterning the nitride layer for supporting storage nodes and the mold insulation layer, support patterns for fixing the storage nodes are formed. Then, a dip-out process is conducted to remove the mold insulation layer having served as a mold for forming the storage nodes. At this time, the support patterns function to prevent the storage nodes from leaning. Next, by sequentially forming a dielectric layer and plate nodes on the storage nodes, cylinder type capacitors are completely formed.
However, in the conventional art as described above, the stress induced when conducting the dip-out process and subsequently forming the dielectric layer to the support patterns contributes to cracks between the support patterns and the storage nodes. As a result, leakage of capacitance is can result which degrades the operational characteristics of a semiconductor devices.